Utilization of Plant Introductions in Soybean Breeding Populations1
- C. S. Schoener and
- W. R. Fehr2
The relationship between percentage of germplasm from plant introductions (PIs) in soybean [Glycine max (L.) Merr.] populations and their performance for seed yield, height, and lodging was evaluated. Five intermated populations were developed from four PIs selected for their good yield potential, PI 68600, PI 68704, PI 81029, and PI 91150, and four cultivars or experimental lines, ‘Chippewa 64’, C1426, L15, and ‘Calland’. The parents and their hybrid progeny were intermated up to five times to form population AP1 with 100% PI germplasm, AP2 with 75%, AP3 with 50%, AP4 with 25%, and AP5 with 0%. Performance of progeny from 96 random S3 plants from each population was evaluated in three environments in Iowa during 1975 and 1976.
Both the linear and quadratic mean squares were significant for differences in yield among the five populations. There was a linear increase in yield from AP1 to AP5; however, AP1 consistently was higher yielding than AP2. AP5 had the highest mean yield and greatest frequency of lines with high yield. AP3 had the greatest amount of genetic variability for yield, AP2 and AP4 were intermediate and AP1 and AP5 had the least. There was a significant linear increase in height from AP1 to AP5 and linear decrease in lodging score from AP1 to AP5.
The use of PIs with good yield potential and up to five intermatings before selection did not overcome the superiority of the population developed from high yielding cultivars and experimental lines. The superiority of AP5 was small enough, however, to suggest that evaluation of PIs for yield may permit selection of parents that do not cause a drastic yield reduction in genetically diverse populations. The acceptable mean yield and high genetic variability of AP3 suggested that up to 50% PI germplasm may be suitable for populations intended for long-term improvement by recurrent selection.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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